Code now import both astropy and system gzip
Code now import both astropy and system gzip

For clarity the astropy gzip is called _astropy_gzip
and the system gzip is called _system_gzip.

All gzip.x statements have been changed to use the
_astropy_gzip.

All isinstances statements check both

aleksandr-bakanov/astropy,dhomeier/astropy,StuartLittlefair/astropy,MSeifert04/astropy,bsipocz/astropy,lpsinger/astropy,MSeifert04/astropy,larrybradley/astropy,pllim/astropy,tbabej/astropy,AustereCuriosity/astropy,pllim/astropy,MSeifert04/astropy,larrybradley/astropy,larrybradley/astropy,stargaser/astropy,dhomeier/astropy,astropy/astropy,lpsinger/astropy,saimn/astropy,mhvk/astropy,funbaker/astropy,mhvk/astropy,joergdietrich/astropy,joergdietrich/astropy,tbabej/astropy,StuartLittlefair/astropy,DougBurke/astropy,bsipocz/astropy,funbaker/astropy,tbabej/astropy,stargaser/astropy,aleksandr-bakanov/astropy,lpsinger/astropy,joergdietrich/astropy,pllim/astropy,tbabej/astropy,kelle/astropy,mhvk/astropy,AustereCuriosity/astropy,AustereCuriosity/astropy,bsipocz/astropy,astropy/astropy,mhvk/astropy,stargaser/astropy,StuartLittlefair/astropy,pllim/astropy,astropy/astropy,bsipocz/astropy,kelle/astropy,funbaker/astropy,lpsinger/astropy,dhomeier/astropy,astropy/astropy,astropy/astropy,saimn/astropy,funbaker/astropy,saimn/astropy,kelle/astropy,AustereCuriosity/astropy,saimn/astropy,StuartLittlefair/astropy,joergdietrich/astropy,pllim/astropy,mhvk/astropy,DougBurke/astropy,kelle/astropy,joergdietrich/astropy,saimn/astropy,DougBurke/astropy,larrybradley/astropy,DougBurke/astropy,tbabej/astropy,larrybradley/astropy,MSeifert04/astropy,aleksandr-bakanov/astropy,stargaser/astropy,kelle/astropy,aleksandr-bakanov/astropy,lpsinger/astropy,dhomeier/astropy,StuartLittlefair/astropy,AustereCuriosity/astropy,dhomeier/astropy